I haven't seen one yet that doesn't pull the stem apart, provided the rivet has been pulled tight enough that the tensile strength of the stem is exceeded. And that's the trick, pulling the head far enough into the 'blind' side to fully wedge the barrel open and assure tightness.
My puller almost always requires two, and quite often three release and re-grip movements to pull enough stem length to complete the squeeze between the 'washer' on the exposed side and the expanding barrel that is hidden.
Try it next time. Press the rivet in the material as far as it will go. Press the puller onto the rivet stem through the center of the 'washer' as far as it will go. Squeeze the puller handle to pull some stem. Release the puller. Press it back onto the rivet 'washer' and squeeze the handle again.
I just replaced the rivets for the awning
feet on the side of the Casita
. Dummy me tried to reduce wind exposure by winding the awning
in while the feet were in the trailer's side. I got so far and then the nearly vertical leg pried the foot holder out.